1. Field of the Invention
The present invention relates to a load state decision apparatus for a servomotor wherein a load current value of a servomotor during operation is sampled and compared with a prescribed value and then the load state of the servomotor is decided based on the result of the comparison.
2. Description of the Prior Art
In the prior art, variable data regarding a servomotor according to the load state of the servomotor during the operation, i.e., the load applied to the servomotor, torque, power, delay, speed or the like is obtained by using a detecting apparatus. As a well-known apparatus, a waveform recording instrument such as an oscilloscope is used, and the waveform is recorded and compared with a standard waveform and the data is determined. There is also known another means where consumption power of the servomotor is measured by using a watthour meter or the like and divided by the measuring time to thereby calculate the effective current which is compared with the rated current. In any case, in order to obtain necessary data, a special converting or detecting apparatus is installed externally and the necessary data is produced based on the data obtained from the converting or detecting apparatus.
In the prior art, when the load state of the servomotor is decided, for example, if an oscilloscope must be used, technical knowledge such as use manner of using the oscilloscope, utilizing a connection terminal, etc. is necessary and thus personal error may be introduced into the decision. Also, for example, use of a watthour meter is troublesome and not practical. Further, the converting or detecting apparatus installed externally increases the cost of the motor or may cause a fault in the system.